Her death on January 19 was announced after a performance of The Mousetrap at Nottingham’s Theatre Royal. Sim had appeared as Mollie Ralston in the original production of Agatha Christie’s thriller alongside her late husband in 1952.

A RADA graduate, she enjoyed a successful film and stage career throughout the 1940s and 1950s. Her theatre appearances including School for Spinsters (Criterion Theatre, 1947), Love’s a Funny Thing (Ambassadors Theatre, 1949) and To Dorothy a Son (1950) and Double Image (1956), both at the Savoy Theatre.

She had been an active supporter of the Actors’ Children’s Trust (formerly the Actors’ Charitable Trust) for more than 60 years.

Sim had been living at the actors’ retirement home Denville Hall since 2013, having been diagnosed with dementia the previous year.

Stephen Waley-Cohen, owner-manager of the St Martins Theatre in the West End, where The Mousetrap has run since 1974, said: “Sheila Sim was a delightful and charming lady, very supportive of all of her family and their varied and successful theatrical careers.

“She was always interested in whatever was happening at RADA too, the academy where she and Richard [Attenborough] had first met as students in the 1940s, where he invited me to join the council. Everyone at The Mousetrap was honoured to be able to dedicate yesterday’s performances in London and Nottingham to her memory.”

He added: “Nearly 50 years after The Mousetrap opened in 1952, Sheila and Richard helped and encouraged us in the creation of Mousetrap Theatre Projects, which takes thousands of disadvantaged young people to the best of West End theatre every year.”

A full obituary will appear in a future issue of The Stage.

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